Is the harry potter place at universal really worth the money? we would have to get a taxi both ways from Disney, then the tickets look expensive and ours are too little to enjoy what I think is at islands of adventure so it really would be just for harry potter

It's not a separate admission. Just another "area" on the park map. The kids would love seeing all the Harry Potter stuff. Diagon Alley is well duplicated and Hogwarts is very impressive as it looms over the park like Cinderella's castle does at MK.

Universal is every bit as expensive per day as Disney and also has a hopper add-on.

We did both parks in a day but my kids were not with us. Still we did the key attractions at both Universal parks and got back down to Downtown Disney in time for our Cap'n Jacks 7:15 dinner reservation